Try to Turn off hardware acceleration and tell us what happen.

Also you known you are in 13.0.1, an unsupported version anymore.

http://www.mozilla.org/en-US/firefox/all.html

thank you

I'm sorta in the same boat. I've yet to install 11.4.402.265 since I such problems with 11.3.300.271 which would not work in FF14. I'm waiting for some more feedback from other users to see if they have problems before I waste another 4 hours on FP. I look forward to comments. I'm Vista 32 bit OS

Hardware acceleration was turned off.

Also tried updating FF to 14.0.1 w/o success.

Not sure if this would have made any difference, but after uninstalling Flash 13.3.300.265, I did not reboot Win7 before to installing 11.4.402.265.

Try to "disable the hardware acceleration" in the Flash Player too :

http://helpx.adobe.com/flash-player/kb/video-playback-issues.html

http://www.macromedia.com/support/documentation/en/flashplayer/help/help01.html

thanks again

Ever since the 11.3.300.262/265/268 updates, I've had hardware acceleration in both FF and Flash Player turned off and they were off during the 11.4.402.265 experience as well.

Again, while the few flash sites I tried seem to work OK, but the slow down was quite evident (e.g. navigating/loading sites, mouse interaction etc.) and when I had 2 Flash instances open, the computer just about died, which was never the case with any of the Flash 11.3.300 versions (e.g. the main issue with 11.3.300 updates was a pop-up window were I had to either decline or accept something).

It was bad enough that I had to uninstalled 11.4.402.265 and finally install 10.3.183.23.

I have tried 11.4.402.265 with firefox 15 beta sound is workin but video is like a slide show and disabling hardware acceleration has no difference.Also is hard to shut down a you tube video have to force shutdown ff in windows. 11.2.0.235 is working but this is no solution in the long run. Hope that adobe can sort out the problem but they dont do anything if nobody complaining. So my advise send emails atleast one a day to adobe and complain about it and hope couple thousand do the same. And sorry for my language im not so good in english. Ps. Installed FF 16 beta and trying soon again.